The effect of endogenous hormones on plant morphology and fruit quality of tomato under difference between day and night temperature

The difference between day and night temperature (DIF) was reported to influence plant morphology and fruit quality, but the mechanism was poorly known. Therefore, controlled-environment experiments were carried out to investigate the mechanism of DIF influenced plant morphology and fruit quality attributes of tomato during fruit stage. Five day/night temperature regimes 16/34, 19/31, 25/25, 31/19 and 34/16°C with respective DIFs of -18, -12, 0, +12 and +18 at a common 25°C mean daily temperature were used. The results showed that gibberellin 3, indoleacetic acid and zeatin content of stem tip were enhanced significantly by positive DIF and inhibited by negative DIF, while abscisic acid was not significantly influenced by DIF. Plant height, stem diameter, fruit diameter and leaf area were enhanced significantly by positive DIF regimes and inhibited by negative DIF regimes. The soluble sugars, vitamin C and soluble protein content increased under positive DIF while decreased under negative DIF. Both plant morphology and fruit quality of tomato were significantly related to endogenous hormones.